This invention relates generally to pressure limiting valves and more particularly to automatic pressure limiting apparatus which terminates fluid pressure flow on the attainment of a predetermined pressure within an object subjected to the pressure.
The control of inflation pressure has long been the subject of development both in conjunction with vehicle tires as well as for the inflation of other objects such as cushioning bags, containers, basketballs and footballs. Traditionally, this inflation process has been carried on by the human intervention method, whereby air is injected into the object to be inflated and periodic pressure checks are taken by an operator with a gauge. Automatic apparatus has been developed as described in the U.S. Patent issued to Kennedy, U.S. Pat. No. 3,026,916, where the injection of pressurized air for fixed intervals of time is used to achieve the desired inflation. In the Kennedy reference a vehicle tire is inflated for successive predetermined periods of time until a preset pressure is sensed and the successive operation interrupted. Another approach has been described by the U.S. Patent issued to Glendmand, U.S. Pat. No. 3,104,675, in which a fluid feed back passage is used to sense the inflation pressure and feed the pressure back to a diaphragm valve which closes and interrupts the inflation pressure conduits. The Glendmand concept, however, is not useful for the inflation of basketballs, footballs, and the like which require a small needle to inject the pressure.
In the present invention there is provided an improved pressure limiting and inflation apparatus in conjunction with a small coaxial needle providing fast and accurate inflation to predetermined pressures regardless of the beginning air volume in the object to be inflated.
Accordingly, the primary object of this invention is to provide an accurate inflation appparatus.
It is a further object of this invention to provide an inflation apparatus which operates in conjunction with an insertable needle for the inflation of basketballs and footballs and the like.
It is still a further object of this invention to provide an adjustable and controllable inflation apparatus.